A low temperature poly-silicon thin film transistor (LTPS TFT) has such advantages as high resolution, rapid response, high brightness, large aperture ratio and high electron mobility.
Currently, the LTPS TFT includes, on a base substrate, an active layer, a gate insulation layer, a gate electrode, a source electrode and a drain electrode. The active layer is made of poly-silicon. An important technique for manufacturing the LTPS TFT includes crystallization methods for converting amorphous-silicon into poly-silicon. The methods may include a non-laser crystallization method and a laser annealing method. In the non-laser crystallization method, the easiest way is to perform solid-phase crystallization (SPC). However, for the SPC, an annealing step needs to be carried out at a temperature of 600° C. for about 10 hours, so it is not suitable for a large-size glass substrate. In the laser annealing method, the most common way is to perform excimer laser annealing (ELA). However, an ELA device is very expensive, so the production cost of the LTPS TFT will be increased.